The term wattle tree refers to members of the plant genus Acacia. Species within this genus can be either trees or shrubs and are also called wattles and thorn trees. The tannin in their thick leaves was first recognized in ancient times for its pharmacological properties. Some species contain organic carbon compounds called alkaloids, which can be harvested for psychoactive purposes.
Wattle tree species can be found as far south as the 43rd parallel in Tasmania, Australia as well as in Argentina. Acacias also inhabit savanna regions on some Caribbean islands, the Jordan River valley, and various parts of Europe and Southern Asia as well as desert locations in the Sinai peninsula and Africa. The plant's name changes depending on the region in which it is found, but the two most common are acacia, usually used in Africa and the Americas, and wattle, used in Australia.
The alternate name for a wattle tree, acacia, comes from the Greek word for thorn. While not every species has thorns, some, such as Acacia collinsii in Central America, do. This allows ants to live within the hollow thorns and protect the tree from any foreign invaders, whether animal or plant.
Leaf formation is most commonly of a pinnate design, which is a feather-like arrangement in which individual leaves grow in pairs directly across from one another on both sides of a branch and continue this pattern to the end of the branch. Flowers found on wattle trees are globular and usually a shade of yellow. The flowers have a long stamen that protrudes from the five petals.
Humans have found numerous uses for acacias since antiquity. Some cultures, especially in Africa and Central America, have been known to employ the acacia as part of their traditional medicine, while others have used it in perfumes, a practice that still exists. Acacias are also prized simply for their ornamental value and harvested for their uniquely grained lumber.
The tannin found in many species of wattle tree, particularly many Australian species, is a highly sought after commodity that is employed in the field of medicine. Some wattle trees contain carbon compounds called alkaloids, which are thought to ward off predators that might otherwise harm the tree. Human societies have used these alkaloids for their psychoactive and hallucinogenic properties. This was a common practice in many tribal religions whose followers lived near the trees. Some individuals use it for recreational purposes as well.